On the high temperature testing of superplastic materials

The simplest test in characterizing the behavior of superplastic materials is the uniaxial tensile test. Since superplasticity is achieved at relatively high temperatures, heat involvement adds so many unpredictable problems to the simplest testing technique. In spite of the vast number of research activities directed towards studying the various aspects of superplastic deformation, there is a lack of a standardized testing procedure that can tackle the various issues associated with high temperature testing. In this work, we attempt to shed some light on the controversial issues associated with high temperature superplastic testing. The effects of various testing procedures and parameters on the accuracy of the results are investigated. We address the issues related to gripping and test sample geometry, heat and temperature effects, and comment on the available testing and analysis procedures. We hope that this study highlights the urgent need to develop a standardized testing approach that takes into account all the important issues affecting high temperature testing.